Frost Line Depth in Harlingen, TX: Frost Rarely Reaches the Ground

No official local value

Frost rarely reaches the ground in Harlingen.

No verified code nearby; verified Texas codes range 0–12 in.

Footings still go at least 12 in (30 cm) below undisturbed ground (IRC R403.1.4).

Source and how we checked

We searched this place’s own code and website and found no published frost line depth.

Climate: 1 night a year at or below 32 °F (NOAA 1991–2020, Harlingen, 1.7 mi).

Checked Oct 2026. Report a correction

Footings Deck Water line Fence post

0–12 inrange of verified Texas codes
1nights a year at or below 32 °F
100%of nearby soil rated “none” for frost action (USDA)

Does Harlingen have an official frost line depth?

No adopted frost line depth found for Harlingen in its official documents (checked Oct 2026). No verified code lies near Harlingen; the Texas codes we verified range from 0 to 12 in. Ask the building department for Harlingen’s own number before you dig.

What frost line depth does Harlingen use for footings under Table R301.2(1)?

Call 811 at least a few working days before you dig, so buried lines are marked.
Confirm the frost line depth with the Harlingen building department.
Ask whether your project needs a permit (decks, larger sheds and footings usually do).
Dig below 12 in (the deepest verified state value) unless the building department tells you otherwise.
Book the footing inspection before you pour concrete.

How deep do footings, decks and water lines need to be in Harlingen?

Drawn with the deepest Texas official value (12 in). Confirm Harlingen’s own depth before you dig.

House or garage footing Deck footing Water service line Fence post

House or garage footing in Harlingen: dig at least 12 in (30 cm). Below the frost line and at least 12 in deep (IRC R403.1.4).

Minimum depths in Harlingen with a 12 in frost line
Project	Depth	Rule
House or garage footing	12 in	Below the frost line and at least 12 in deep (IRC R403.1.4)
Deck footing (attached)	12 in	Below the frost line and at least 12 in deep (IRC R507.3)
Water service line	18 in	6 in below the frost line and at least 12 in deep (IRC P2603.5)
Fence post bottom	12 in	No code rule; common practice is below the frost line

Work out posts, concrete and footing sizes with the fence post depth calculator or the deck footing calculator.

How cold does it get in Harlingen?

Harlingen never averages a low below freezing. 1 night a year reach 32 °F or colder; Jan is coldest, with an average low of 51.1 °F.

NOAA 1991–2020 climate normals, Harlingen station, 1.7 mi away, elevation 38 ft.

Monthly temperatures as a table

°F	Jan	Feb	Mar	Apr	May	Jun	Jul	Aug	Sep	Oct	Nov	Dec
Low	51.1	54.8	60	65.9	71.8	75.9	76.9	76.8	73.6	66.8	58.8	52.5
High	71.7	76	81	86.4	91.1	95.4	96.6	97.8	93.1	88	79.7	73.2

Harlingen has fewer freezing nights than 159 of the 168 other Texas places we track. The Texas median is 32. Coldest: Amarillo; mildest: Brownsville.

How likely is the soil in Harlingen to heave?

None 100%

USDA rates the sampled soil around Harlingen as 100% none for frost action (main soils: Mercedes, Raymondville, Racombes).

USDA NRCS soil survey, 9 sample points within 2 mi. Higher frost action means more risk of heave; see frost heave.

Harlingen at a glance

Frost line depth: No official local value
County: Cameron County
Population (2023 est.): 71,510
Mean annual temperature: 75.6 °F
ZIP codes (3): 78550 · 78552 · 78586